This invention relates to traversing a strand or strands to form a restrained cross-laid web. More particularly, it relates to an improved method for traversing a plurality of strands with good precision of laydown at high speed to form a restrained web.
Patent application Ser. No. 718,338 filed Aug. 27, 1976, now U.S. Pat. No. 4,030,168, granted June 21, 1977, of common assignee, discloses a method of traversing a strand between two pin conveyors in a plane transverse to the plane of the conveyors wherein a loop in the strand is formed, turned out of the plane of traverse, and then deposited on the pins of one of the conveyors, after which the strand is traversed in the same way to the other conveyor and the cycle is repeated. In the method described, the strand is slideably engaged by a hook rotating in the plane of traverse and is then also slideably engaged by a spreader rotating in a plane skewed to the plane of the hook. In the embodiments disclosed, the spreader travels closely behind the hook at the same peripheral speed as it moves across the plane of the hook. The hook and the spreader together form a loop in the strand which is traversed across the row of pins on one conveyor and doffed. Since the spreader is traveling slightly behind the hook in the embodiments disclosed, and since the doffing action is not completed until the spreader has crossed the row of pins, a considerable length of srand is contained within the loop beyond the row of pins at the time of doff. Since the loop thus contains considerable slack, it tends to be pulled against the pins with a jerk. The lack of smooth doffing action tends to limit the speed at which the web can be laid down.